1. Technical Field
Example embodiments are disclosed herein that relate to an organic memory device and a method for fabricating the same. More specifically, example embodiments are disclosed herein that relate to an organic memory device comprising an organic memory layer and a metallic nanoparticle layer formed between a first electrode and a second electrode, and a method for fabricating the organic memory device.
2. Description of the Related Art
Recent dramatic advances in information communication industry and portable information device technology have led to an increasing demand for large-capacity, nonvolatile memory devices. Most currently-available nonvolatile memories are flash memories based on silicon materials. However, conventional flash memories suffer from the technical limitations in that the number of writing/erasing cycles is limited, the writing speed is slow, and miniaturization and high integration of the devices are difficult. In light of these circumstances, much research has been conducted on next-generation nonvolatile memory devices.
For example, great effort is now being actively undertaken to develop next-generation nonvolatile memory devices using an organic material and a polymer as materials for a memory layer of the memory devices to overcome the physical limitations of conventional silicon-based memory devices and achieve the advantages of ultrahigh speed, large capacity, low power consumption, and low cost.
Switching modes of an organic memory device using an organic material and a polymer includes a mode in which electrons are captured by metallic nanoparticles combined with the organic material to induce variations in the resistance of the organic memory device; a mode in which ionic salts contained in a conductive polymer induce variations in the resistance of the organic memory device depending on the distribution of ions; a mode in which the organic memory device is switched by controlling the formation and short-circuiting of metal filaments within an organic memory layer; a mode in which the organic memory device is switched by changing the structural configuration and redox states of molecules present in an organic memory layer; and other switching modes as well.
Organic memory devices (also termed metal filament memories) are currently being investigated as new-generation memory devices. Metal filament memories utilize a phenomenon where resistance values are varied by the formation and short-circuiting of metal filaments within an organic memory layer that are present between two electrodes. Metal filament memories become an ‘ON’ state (a low resistance state) when metal filaments are formed, and an ‘OFF’ state (a high resistance state) when metal filaments are short-circuited. A voltage or a pulse signal higher than a critical value is applied to an organic memory device to write data in a memory cell, and a voltage or an electric field having a polarity is applied to the organic memory device to read data from the memory cell. On the other hand, to erase data written in the memory cell, a voltage or a pulse having a polarity opposite to that of the writing signal is applied to the organic memory device.
As explained above, conventional organic memory devices are operable only when both positive and negative voltages are applied thereto, thus necessitating the use of a plurality of transistors. Accordingly, 1-diode 1-resistor (1D1R) memory devices cannot be realized, which makes it difficult to achieve miniaturization and high integration of the memory devices.